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Nuclear Theory·nucl-th

Friday·March 19, 2021

13 papers—4 primary·9 cross-listed

All13Primary4Cross-lists9
  1. 01

    Exploring theoretical uncertainties in the hydrodynamic description of relativistic heavy-ion collisions

    Cheng Chiu🇺🇸 · Chun Shen🇺🇸

    We explore theoretical uncertainties in the hydrodynamic description of relativistic heavy-ion collisions by examining the full non-linear causality conditions and quantifying the second-order transport coefficients' role on flow observables. The causality conditions impose physical constraints on the maximum allowed values of inverse Reynolds numbers during the hydrodynamic evolution. Including additional second-order gradient terms in the Denicol-Niemi-Molnár-Rischke (DNMR) theory significantly shrinks the casual regions compared to those in the Israel-Stewart hydrodynamics. For Au+Au collisions, we find the variations of flow observables are small with and without imposing the necessary causality conditions, suggesting a robust extraction of the Quark-Gluon Plasma's transport coefficients in previous model-to-data comparisons. However, sizable sensitivity is present in small p+Au collisions, which poses challenges to study the small systems' collectivity.

    nucl-thhep-phnucl-exPRC(2021)·53 citations
  2. 02

    Delta Baryons in Neutron-Star Matter under Strong Magnetic Fields

    Veronica Dexheimer🇺🇸 · Kauan D. Marquez🇧🇷 · Débora P. Menezes🇧🇷

    In this work, we study magnetic field effects on neutron star matter containing the baryon octet and additional heavier spin 3/2 baryons (the 's). We make use of two different relativistic hadronic models that contain an additional vector-isovector self interaction for the mesons: one version of a relativistic mean field (RMF) model and the Chiral Mean Field (CMF) model. We find that both the additional interaction and a strong magnetic field enhance the baryon population in dense matter, while decreasing the relative density of hyperons. At the same time that the vector-isovector meson interaction modifies neutron-star masses very little (), it decreases their radii considerably, allowing both models to be in better agreement with observations. Together, these features indicate that magnetic neutron stars are likely to contain baryons in their interior.

    nucl-thastro-ph.HEhep-thEPJA(2021)·35 citations
  3. 03

    Nuclear energy density functionals from empirical ground-state densities

    Giacomo Accorto🇭🇷 · Tomoya Naito🇯🇵 · Haozhao Liang🇯🇵 · Tamara Niksic🇭🇷 · Dario Vretenar🇭🇷

    A model is developed, based on the density functional perturbation theory and the inverse Kohn-Sham method, that can be used to improve relativistic nuclear energy density functionals towards an exact but unknown Kohn-Sham exchange-correlation functional. The improved functional is determined by empirical exact ground-state densities of finite systems. A test of the model and an illustrative calculation are performed, starting from two different approximate functionals, to reproduce the parameters and density dependence of a target functional, using exact ground-state densities of symmetric N=Z systems.

    nucl-thPRC(2021)·5 citations
  4. 04

    Quarkyonic stars with isospin-flavor asymmetry

    J. Margueron🇫🇷 · H. Hansen🇫🇷 · P. Proust🇫🇷 · G. Chanfray🇫🇷

    We suggest an extension to isospin asymmetric matter of the quarkyonic model from McLerran and Reddy. This extension allows us to construct the -equilibrium between quarks, nucleons and leptons. The concept of the quarkyonic matter originates from the large number of color limit for which nucleons are the correct degrees of freedom near the Fermi surface -- reflecting the confining forces -- while deep inside the Fermi sea quarks naturally appear. In isospin asymmetric matter, we suggest that this new concept can be implemented within a global isoscalar relation between the shell gaps differentiating the nucleon and the quark sectors. In addition, we impose the conservation of the isospin-flavor asymmetry in the nucleon and the quark phases. Within this model, several quarkyonic stars are constructed on top of the SLy4 model for the nucleon sector, producing a bump in the sound speed, which implies that quarkyonic stars are systematically bigger and have a larger maximum mass than the associated neutron stars. They also predict lower proton fraction at -equilibrium, which potentially quenches fast cooling in massive compact stars.

    nucl-thastro-ph.HEhep-phPRC(2021)·54 citations

Affiliations

first authorsco-authorsvia INSPIRE